Improvement in lamp-chimneys



G. L. WITSIL.

Lamp Chimney.

No. 55,436. I Patented June 5, 1866.

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UNITED STATES PATENT OFFICE.

GEORGE L. WVITSIL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HIM- SELF AND JOHN F. OABOT, OF ELIZABETH, NEW JERSEY.

IMPROVEMENT IN LAM P-CHIMNE YS.

Specification forming part of Letters Patent No. 55,436, dated June 5, 1866.

To all whom it may concern:

Be it known that I, GEORGE L. WITSIL, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a new and Improved Lamp-Chimney; and [do hereby declare that the I'ollowin is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making apart of this specification, in which- Figure I is a side view of my improved lampchimney. Fig. 2 is a diametrical section through the chimney. Fig. 3 is a top view.

Similar letters of reference indicate corresponding parts in the several figures.

The object of this invention is to so construct glass chimneys for lamps that while they shall not be very liable to crack in consequence of sudden changes of temperature, the chimneys shall also serve a much better pur 'iose than lamp-chimneys hitherto used for promoting the combustion of carbon and pre venting the escape of smoke from the flame of a lamp, as will be hereinafter described.

To enable others skilled in the art to understand my invention, I will describe its construction and operation.

The general form of the lamp-chimney may be that represented in the drawings, or any other form may be adopted which will answer a good purpose. A spiral groove is formed in the chimney, commencing at-a point where the chimney, begins to contract in diameter and terminating at the upper end of the chimney. The groove 60 may diminish in depth as it rises, so that it will terminate at the upper end of the chimney in a comparatively shallow groove, as represented in the drawings. By thus forming a spiral depression or groove, a, correspondin g elevations are formed, as at I) b, so that an elevation on the outside of the chimney produces a depression on the inside of the chimney, and vice versa. In this way the air which impinges upon the glass surface where it is grooved will be directed upward in a spiral current. This is particularly the case 011 the inside of the chimney, where the elevavations b are more shelving, so as to retain the heated air for a comparatively long time to circulate a number of times around the chimney in its ascent through it. The air bein g in this manner retarded in its escape from the chimney will become very highly heated, and thus assist materially in the combustion of the carbon and the prevention of smoke.

The chief object of my invention is to prevent as far as possible glass chimneys from crackingin consequence of a too sudden change of temperature, or rather to prevent a too sudden cooling or heating of the chimney. The cool air, which rushesinto the base of the lam pchimney as soon as the lamp is lighted, will become heated and rise toward the opening at the top of the chimney. Some of this air will pass up through the center of the chimney and immediately escape, while another portion,

which is nearer the surface of the chimney,

will be arrested in its direct upward course and caused to circulate around the interior of the chimney in the groove or spiral channel a, at the same time imparting heat to the glass chimney. In this way the chimney will be nearly uniformly heated throughout.

,These spirally-grooved chimneys may be readily made in molds which are made in sections and "properly grooved, the glass being blown into the molds so as to assume theform thereof. In all other respects the chimneys may be made like those which have been commonly used.

The groove or spiral channel on the outside surface of the chimney has the effect of retaining heated air about this outside surface and preventing to a considerable degree the sudden cooling of this surface by currents of cold air impinging upon it.

Having described myinvention, what I claim as new, and desire to secure by Letters Patcut, is

A lamp-chimney Which has the winding or spiral groove formed in it, substantially as described.

Witness my hand in matter of my application for a patent for improved lamp-chimney.

,GEO. L. VITSIL.

Witnesses:

R. T. CAMPBELL, Enw. SGHAFER. 

